Image Processing docs

[simmplecoder]

Description

Expanded documentation for Harris and Hessian detectors.

References

#350, #364

Tasklist

• Check if the docs are in the final output
• Ensure all CI builds pass
• Review and approve

[mloskot]

First, thank you very much for kickstarting the prose documentation for the image processing. I hope @miralshah365 will also fill it in with some content.

Since we rely on Sphinx, see https://github.com/boostorg/gil/blob/develop/doc/README.md, all prose docs must be written in reStructuredText, not Markdown.

Second, in order to tell Sphinx to integrate your pages, you need to add to the table of contets in the doc/index.rst lines like this

image_processing/basics
image_processing/<other page without .rst extension>

e.g. somewhere after design_guide and before extensions.

[stefanseefeld]

I agree with @mloskot : markdown documentation such as the toplevel *.md files is intended to be browsed by contributors who review the repo on github (which provides markdown rendering built into their portal) or quickly glance over them in purely textual form on your local machine.
Any end-user documentation (tutorials, API docs, etc.) needs a bit more care, i.e. is actually compiled into html and possibly other formats using sphinx. This is published online in https://boostorg.github.io/gil.
Build the docs locally by running bjam / b2 inside gil/doc and review the generated HTML to make sure your changes are compiled correctly.

[mloskot]

Any reason you don't follow GIL's markup for headings?

GIL (should) follows markup for sections recommended by Python guide for documenting and equivalent Sphinx reStructuredText Primer, that is:

=, for sections
-, for subsections
^, for subsubsections
", for paragraphs

However, in future, this may and we may decide to distinguish chapters and parts as well.is intentional.

[mloskot]

This looks good to me.

I just had a general comment in #388 (review)